What are the two types of mobile gantry cranes?

Mobile gantry cranes are versatile lifting equipment used in various industries, and they can be broadly categorized into two main types based on their mobility and structure:  
1. Fixed Height Mobile Gantry Cranes  
   - These cranes have a fixed beam height and cannot be adjusted.  
   - They are portable and often equipped with swivel casters or wheels for easy movement.  
   - Ideal for workshops, warehouses, and loading/unloading tasks where lifting height requirements are consistent.  

2. Adjustable Height Mobile Gantry Cranes 
   - Feature an adjustable beam (manual or hydraulic) to vary the lifting height as needed.  
   - Provide greater flexibility for different load sizes and workspace constraints.  
   - Commonly used in maintenance, construction, and industrial applications where varying lift heights are required.  

Both types can be further classified based on load capacity, wheel type (fixed or swivel), and material (steel or aluminum). Mobile gantry cranes are popular due to their ease of movement, no need for permanent installation, and cost-effectiveness compared to overhead cranes.